Total organic carbon content vs. Mo concentration ([TOC] vs. [Mo]) diagrams for samples from the Tithonian-Berriasian interval. The solid lines represent four present-day basins characterized by restriction of water mass circulation. The degree of restriction increases from the Saanich Inlet to the Black Sea. See explanations given in Algeo and Lyons (2006) and Algeo et al. (2007). The four reference settings (Saanich Inlet, Cariaco Basin, Framvaren Fjord and Black Sea) are characterized by increasing water mass restriction due to hydrological conditions. This limits the replenishment of dissolved Mo coming from the open sea, which may lead to exhaustion of this element in the case of massive scavenging from the water column down to the sediment. The samples with the highest TOC values straddle fields on the diagram reflecting increasing restriction and dissolved-Mo drawdown. The TOC-enriched samples are located in the lower part of the section, which tends to indicate that the depositional environment underwent episodic restriction of water mass circulation during deposition of the lower part of the Vaca Muerta Formation.